KR100524199B1 - Continuous Variable-Copolymer Preparation Method - Google Patents

Abstract

A process for producing a continuous variable-composition copolymer is disclosed by causing a gradual change in the monomer composition during the polymerization. The poly (meth) acrylate copolymers produced by the process of the invention have the properties of improved lubricant additives, such as, for example, as pour point depressants, compared to the relevant polymer additives prepared by conventional methods.

Description

Process for preparing continuous variable-copolymer

The present invention relates to a process for preparing a continuous variable-composition copolymer by causing a gradual change in monomer composition during the polymerization process. An application of the method is a poly (meth) acrylate air having improved lubricating oil additive properties, for example, as a pour point depressant or viscosity index improver when compared to related polymer additives prepared by conventional methods. Preparation of coalescence.

The behavior of petroleum oil blends under cold flow conditions is greatly influenced by the presence of paraffins (waxes) that crystallize from the oil upon cooling. These paraffins greatly reduce the fluidity of the oil at low temperatures. Polymeric flow improvers, known as pour point depressants, have been developed to effectively lower the "flow point" or freezing point of an oil under certain conditions (ie, the lowest temperature at which the blended oil is present as a fluid). Pour point depressants are effective at very low concentrations, such as, for example, 0.05 to 1% by weight in oil. The pour point depressant material itself incorporates into the growth paraffin crystal structure, effectively preventing further crystal growth and the formation of elongated crystal masses, allowing the oil to be in fluid state at the lowest possible temperature.

One limitation of the use of pour point depressant polymers is that not all polymeric pour point depressants are consistently effective in reducing the pour point of different petroleum oils, since petroleum oils from different sources contain different types of waxy or paraffinic materials. That is, polymeric pour point depressants may be effective for one type of oil and may not be effective for another. It would be desirable for a single pour point depressant polymer to be useful in a wide range of petroleum oils.

One approach to solving this problem is described in "Depression Effect of Mixed Pour Point Depressants for Crude Oil" by B. Zhao, J. Shenyang, Inst. Chem. Tech., 8 (3), 228-230 (1994), wherein in two different crude oil samples by using a physical mixture of two different conventional pour point depressants than when using pour point depressants in oil separately. Improved pour point performance was obtained. Similarly, U.S. Pat.No. 5,281,329 and EP 140,274 describe methods of using physical mixtures of different polymeric additives to obtain improved pour point properties compared to using each polymer additive alone in lubricating oils. It is.

U.S. Patent No. 4,048,413 controls the rate and rate of addition of monomers added to the polymerization mixture of monomers to counteract fundamental differences in the reactivity of individual monomers that typically lead to compositional "drift" during conventional polymerizations. A method for preparing a homogeneous-copolymer is described. No. 4,048,413 discloses no control of the rate and rate of addition of monomers into the polymerization mixture to provide a continuous change or continuous variable-composition copolymer.

When homopolymer additives are used in a wide range of lubricant formulations, none of these approaches provide good low temperature flowability.

It is therefore an object of the present invention to provide a process for preparing a copolymer having a continuous variable-composition, in which it also provides a polymer having a combination of the desired lubricating oil properties in a single polymer additive.

The present invention,

(A) forming a first reaction mixture comprising a monomer-containing phase wherein at least two copolymerizable monomers are present in a weight percent ratio of X ₁ / Y ₁ to Y ₁ / X ₁ ,

(B) forming at least one addition reaction mixture comprising a monomer-containing phase wherein at least two copolymerizable monomers are present in a weight percent ratio of X _n / Y _n to Y _n / X _n ,

(C) initiating free-radical addition polymerization by gradually adding a first reaction mixture or a mixture of said first reaction mixture with at least one addition reaction mixture to the reactor under polymerization conditions, (c)

(D) continuing the polymerization by gradually adding one or more addition reaction mixtures to the reactor (i) or to the first reaction mixture (ii) to be added to the reactor at a point before the first reaction mixture is added to the reactor and

(E) maintaining the polymerization conditions until at least 90% of the at least two copolymerizable monomers are converted to copolymers, wherein X ₁ and Y ₁ are selected from the two or more copolymerizable monomers in the first reaction mixture. Weight percent of any two X and Y monomers, X _n and Y _n are weight percent of any two X and Y monomers of the two or more copolymerizable monomers in one or more addition reaction mixtures, and X ₁ , X _n , Y ₁ and Y _n are values from 0 to 100%, n is a continuous integer from 2 to 10 corresponding to each of one or more addition reaction mixtures containing similar X _n and Y _n weight percents, and the maximum value of n is The total number of reaction mixtures used in the process, wherein the gradual addition of one or more addition reaction mixtures in step (d) results in at least one of the absolute values of [X _i -X _T ] or [Y _i -Y _T ] More than%, X _i , X _T , Y _i and Y _T are initially (X _i and Y _i ) and how much Later (X _T and Y _T ) is the instantaneous weight percent of any two X and Y monomers added to the reactor].

The present invention also provides a variable-composition copolymer prepared by the above process, wherein the copolymerizable monomer is a vinylaromatic monomer, a nitrogen-containing ring compound monomer, an α-olefin, vinyl alcohol ester, vinyl halide, vinyl nitrile, ( Meth) acrylic acid derivatives, maleic acid derivatives and fumaric acid derivatives.

The present invention also provides a method for maintaining low temperature fluidity of a lubricating oil composition, comprising adding 0.05 to 3% by weight of the variable-composition copolymer prepared according to the above method to the lubricating oil.

In another embodiment, the present invention provides a continuous variable-composition copolymer comprising at least four different single-composition copolymers, wherein no single-composition copolymer exceeds 50% by weight of the variable-composition copolymer Single-composition copolymers include methyl methacrylate, butyl methacrylate, isodecyl methacrylate, lauryl-myristyl methacrylate, dodecyl-pentadecyl methacrylate, cetyl-eicosyl methacrylate and cetyl- Having monomeric units selected from two or more of stearyl methacrylates.

As used herein, the term "alkyl (meth) acrylate" refers to the corresponding acrylate or methacrylate ester, and similarly, the term "(meth) acrylic acid" refers to the corresponding acrylic acid or methacrylic acid and derivatives. do. As used herein, all percentages mentioned will be expressed in weight percent based on the total weight of polymer or composition included unless otherwise indicated. As used herein, the term "copolymer" or "copolymer material" means a polymer composition containing two or more monomers or units in the form of monomers.

As used herein, the term "gradual addition" refers to the continuous or discontinuous addition of monomers, monomer mixtures or monomers, in a drop or stream over time, e.g., different monomers or monomer mixtures. Separate feed to the polymerization reactor (reaction vessel), or using an in-line mixing apparatus, which combines the independent monomer mixtures at a point prior to adding one monomer mixture to the reactor, or By directly feeding one monomer mixture to a storage container of another monomer mixture, an independent metered supply of different monomers or monomer mixtures can be provided which can change the relative ratio of monomers to provide the desired effect. As used herein, “intermittent” addition does not exceed about 50% of the single-composition copolymer (based on the monomer ratio in the reactor) within the range of the copolymer composition formed during the polymerization. This means that the addition of the monomer feed to the reactor or in-line mixer is briefly interrupted as long as it corresponds to the theoretical formation. Discontinuous addition also includes multiple discontinuous addition of monomers or monomer mixtures, wherein the composition of the monomer mixture in each discontinuous addition differs by at least 5% in at least one of the compositions of other discontinuous additions and at least one component of the monomer mixture and any discontinuous monomers. The maximum contribution of the addition corresponds to less than 50% of the single-composition copolymer (based on the monomer ratio in the reactor) within the range of the copolymer composition formed during the polymerization.

As used herein, "theoretical formation" refers to the full range of effective copolymer compositions, assuming that all monomers added to the polymerization medium are actually converted to the copolymer immediately (in the proportions indicated by the compositional environment at hand). Corresponds to the amount (% by weight) of the particular single-component copolymer formed in part. For example, if 10% of the total monomer feed during polymerization corresponds to a single X / Y copolymer composition, the final copolymer material will theoretically contain 10% of that single composition. When the monomer is fed into the polymerization medium under conditions not corresponding to the polymerization conditions, such as cooling the reaction mixture to a temperature at which little or no polymerization occurs, the particular copolymer composition formed during this period will set or reset the polymerization conditions. It will be based on the theoretical formation of the copolymer composition corresponding to the average composition applied to the reactor before.

As used herein, "under polymerization conditions" means conditions in the polymerization reactor sufficient to substantially introduce any monomer present into the copolymer. That is, for example, the combination of temperature, form of free-radical initiator, and any optional promoter has a half life of the initiator system of less than about 2 hours, preferably less than 1 hour, more preferably less than 10 minutes, most preferably Provides an environment that is less than about 5 minutes.

As used herein, the term "continuous variable-composition" means a copolymer composition in which a single-composition copolymer is distributed in a copolymer material, ie, a copolymer material derived from a single polymerization method. The distribution of the single-composition copolymer is 50% or less, preferably 20% or less, more preferably about 10% or less, most preferably any single-composition copolymer within the distribution range of the single-composition copolymer in the copolymer material. Preferably at least 5% and at least 4, preferably at least 10, more preferably at least 20 different single-composition copolymers should comprise a continuously-variable composition copolymer.

For the purposes of the present invention, copolymers having a continuously-variable composition satisfy the above requirement that up to 50% of any single-composition copolymer is present in the copolymer material, while monomers of the single-composition copolymer in the range of the copolymer composition are present. Or at least 5%, preferably at least 10%, more preferably at least 20%, most preferably at least 30% in at least one of the monomeric form components. Single-composition copolymers are defined as copolymers most similar to themselves and copolymers that are at least 1% different in at least one monomeric component.

For example, a copolymer material containing a single-component copolymer ranging from 70 monomer X / 30 monomer Y to 30 monomer X / 70 monomer Y (when using the initial 70X / 30Y monomer mixture and 30X / 70Y at the end of monomer feed) Prepared by polymerizing the monomer mixture composition continuously until), the 61X / 39Y component is considered to be a single-composition copolymer and the 62X / 38Y component is considered to be a different single-composition copolymer. Using this example to further illustrate the concept of a continuous variable-composition copolymer, the composition of the monomer feed to be polymerized is continuously throughout the polymerization process from one extreme of the X / Y composition to the other extreme of the X / Y composition. Assuming controlled, the copolymer composition theoretically contains at least 40 different single-copolymers, each of between 70X / 30Y and 30X / 70Y, based on the theoretical formation of each single-copolymer during polymerization. 1% different. In this case the copolymer material theoretically has about 2.5% of each of the 40 different single-compartment copolymers, each of which can be explained that the successive increments differ by 1% X and 1% Y. However, the first 20% of the monomers fed with polymerization have a constant composition of 70X / 30Y, the next 20% at 60X / 40Y, then 20% at 50X / 50Y, then 20% at 40X / 60Y, And if the polymerization is carried out so that the last 20% has a constant composition at 30X / 70Y, in this case the copolymer material theoretically has about 20% of each of the five different single-adjusted copolymers, each about 10% X It can be explained that they differ by as much as 10% Y.

An advantage of the process of the invention is the ability to vary the number of different single-composition copolymers formed in a single polymerization process. The polymerization process can be multistage and include single or multiple reactors. However, the process is a single continuous in contrast to the preparation of different copolymers (in separate polymerizations) (see, eg, US Pat. No. 5,281,329 and EP 140,274) which combine to produce a physical mixture of single-composition copolymers. A method for preparing a variable-composition copolymer is disclosed. In this way, the copolymers are conveniently adapted to the particular end application requiring them without the need for multiple polymerization reactions and the separation and storage of different copolymers to provide blending additive compositions.

There is no limit to the extremes of the individual composition ranges within a given copolymer material produced by the process of the invention. For example, a copolymer material having an overall average composition of 50X / 50Y may consist of individual single-component copolymers in the range of 100X / 0Y to 0X / 100Y or only in the range of 55X / 45Y to 45X / 55Y. In a similar manner, copolymer materials having an overall average composition of 80X / 10Y / 10Z, where Z is the third monomer, are for example 100X / 0Y / 0Z to 40X / 10Y / 50Z or only 75X / 20Y / 5Z to 85X. It can consist of individual single-composition copolymers in the range / 0Y / l5Z.

There is no limit to the number or monomer form of monomers used to prepare the continuous variable-composition copolymer of the present invention. Different monomers may be combined into one or more reaction mixtures to add to the reactor or different monomers may each represent a separate reaction mixture. Typically, as many as 10 different reaction mixtures can be used, but the number n of reaction mixtures used is two (2). Depending on the desired end result, the monomer-containing phases of the reaction mixture may each comprise different monomers or monomer forms, or combinations of different monomers or monomer forms. For example, when using four different monomers such as methyl methacrylate, lauryl-myristyl methacrylate, cetyl-stearyl methacrylate and hydroxypropyl methacrylate, each monomer may be added to the reactor. Separate reaction mixtures (n = 4) or only two reaction mixtures may be used, each of which is (i) methyl methacrylate / cetyl-stearyl methacrylate or methyl methacrylate / hydride, for example. Contain two or more monomers in different proportions, such as oxypropyl methacrylate, and the concentration of the remaining monomers does not change, or (ii) each contains any three monomers in different proportions, and the fourth monomer concentration is constant or , (iii) each contains all four monomers at different concentrations.

In order to control the introduction of significantly different reactive monomers, such as (meth) acrylic acid esters and styrene derivatives, multiple monomer feeds may have different feed rates. If desired, control of the copolymer composition can be derived from the application of well known copolymer schemes based on the use of monomer reactivity ratios. See Textbook of Polymer Science, FW Billmeyer, Jr., pp 310-325. (1966)]. US Pat. No. 4,048,413 describes the use of monomer reactivity ratios and the addition of increasing amounts of more reactive monomer components of the desired copolymer during polymerization to obtain a constant composition copolymer. Contrary to the teachings and objectives of US Pat. No. 4,048,413, the process of the present invention is for providing a continuously-changing composition or a continuously-variable composition copolymer during a single polymerization process.

Preferably, the process of the invention is carried out to produce copolymer materials having a large number of individual single-composition copolymers whose ranges are extreme in the copolymer composition set by the monomer feed conditions and monomer ratios. The change in composition of the monomer feed during the polymerization is not limited to uniformly increasing or decreasing from the initial composition to the designated final sheath. For example, in going from the initial 70X / 30Y composition to the final 30X / 70Y composition, it is not necessary to proceed smoothly from initial to final conditions. The X / Y ratio of the monomer feed may increase at any point during the feed (eg below 80X / 20Y), remain constant or decrease (eg below 20X / 80Y). All that is required is to meet the overall requirements defining the preparation of continuous-variable compositional copolymers:

(1) no single-composition copolymer composition exceeds 50% of the copolymer material within the range of single-composition copolymer defining the copolymer material,

(2) the copolymer material must contain an individual single-component copolymer having at least 5% difference between at least one of the monomeric or monomeric form components of the single-component copolymer,

(3) the copolymer material must contain at least four different single-composition copolymers,

(4) A single-composition copolymer is defined as having a composition that is at least 1% different in its most similar composition and at least one monomeric component of the composition.

Monomers useful in practicing the methods of the present invention may be monomers capable of polymerizing with comonomers and being relatively soluble in the copolymer formed. Preferably, the monomer is a monoethylenically unsaturated monomer. Polyethylene-based unsaturated monomers that are crosslinked during polymerization are generally undesirable. Polyethylenically unsaturated monomers that are not crosslinked or crosslinked to a small extent are, for example, butadiene and are also satisfactory comonomers.

One class of suitable monoethylenically unsaturated monomers are, for example, vinyl, including styrene, α-methylstyrene, vinyltoluene, ortho-, meta- and para-methylstyrene, ethylvinylbenzene, vinylnaphthalene and vinylxylene Aromatic monomers. Vinylaromatic monomers are also halogenated derivatives containing one or more halogen groups, such as, for example, fluorine, chlorine or bromine, and nitro, cyano, alkoxy, haloalkyl, carvalkoxy, carboxy, amino and alkylamino derivatives. And their corresponding substitution counterparts, such as.

Other classes of suitable monoethylenically unsaturated monomers are, for example, vinylpyridine, 2-methyl-5-vinylpyridine, 2-ethyl-5-vinylpyridine, 3-methyl-5-vinylpyridine, 2,3-dimethyl -5-vinylpyridine, 2-methyl-3-ethyl-5-vinylpyridine, methyl-substituted quinoline and isoquinoline, 1-vinylimidazole, 2-methyl-1-vinylimidazole, N-vinylcapro Nitrogen-containing ring compounds such as lactam, N-vinylbutyrolactam and N-vinylpyrrolidone.

Another class of suitable monoethylenically unsaturated monomers are, for example, α-olefins such as propylene, isobutylene and long chain alkyl α-olefins such as (C ₁₀ -C ₂₀ ) alkyl α-olefins, vinyl acetate And vinyl nitriles such as acrylonitrile and methacrylonitrile, vinyl halides such as vinyl alcohol esters such as vinyl stearate, vinyl chloride, vinyl fluoride, vinyl bromide, vinylidene chloride, vinylidene fluoride and vinylidene bromide, (Meth) acrylic acid and derivatives (e.g. the corresponding anhydrides, amides and esters), maleic acids and derivatives (e.g. the corresponding anhydrides, amides and esters), fumaric acid and derivatives (e.g. the corresponding amides and esters), and itaconic acid and Ethylene and substituted ethylene monomers such as citraconic acid and derivatives such as the corresponding anhydrides, amides and esters.

Preferred classes of (meth) acrylic acid derivatives are typically alkyl (meth) acrylates, substituted (meth) acrylates and substituted (meth) acrylamide monomers. Each of the monomers may be a single monomer or a mixture having different numbers of carbon atoms in the alkyl moiety. Preferably, the monomer is (C ₁ -C ₂₄ ) alkyl (meth) acrylate, hydroxy (C ₂ -C ₆ ) alkyl (meth) acrylate, dialkylamino (C ₂ -C ₆ ) alkyl (meth) It is selected from the group consisting of acrylates and dialkylamino (C ₂ -C ₆ ) alkyl (meth) acrylamides. The alkyl portion of each monomer can be linear or branched.

Particularly preferred polymers useful in the process of the invention are poly (meth) acrylates derived from the polymerization of alkyl (meth) acrylate monomers. Examples of alkyl (meth) acrylate monomers (also known as "low-cut" alkyl (meth) acrylates) having 1 to 6 carbon atoms in the alkyl group are methyl methacrylate (MMA), methyl and ethyl Acrylates, propyl methacrylates, butyl methacrylate (BMA) and acrylates (BA), isobutyl methacrylate (IBMA), hexyl and cyclohexyl methacrylates, cyclohexyl acrylates and mixtures thereof. Preferred low-cut alkyl methacrylates are methyl methacrylate and butyl methacrylate.

Examples of alkyl (meth) acrylate monomers (also called "mid-cut" alkyl (meth) acrylates) having 7 to 15 carbon atoms in the alkyl group are 2-ethylhexyl acrylate (EHA), 2 Ethylhexyl methacrylate, octyl methacrylate, decyl methacrylate, isodecyl methacrylate (IDMA, based on branched (C ₁₀ ) alkyl isomer mixtures), undecyl methacrylate, dodecyl methacrylate Rate (also known as lauryl methacrylate), tridecyl methacrylate, tetradecyl methacrylate (also known as myristyl methacrylate), pentadecyl methacrylate, and mixtures thereof. See also dodecyl-pentanedecyl methacrylate (DPMA), dodecyl, tridecyl, a mixture of linear and branched isomers of tetradecyl and pentadecyl methacrylate, and lauryl-myristyl methacrylate (LMA), dodec Mixtures of yarns and tetradecyl methacrylates are useful. Preferred mid-cut alkyl methacrylates are lauryl-myristyl methacrylate, dodecyl-pentadecyl methacrylate and isodecyl methacrylate.

Examples of alkyl (meth) acrylate monomers (also known as "high-cut" alkyl (meth) acrylates) having 16 to 24 carbon atoms in the alkyl group are hexadecyl methacrylate (cetyl methacrylate). Also known), heptadecyl methacrylate, octadecyl methacrylate (also known as stearyl methacrylate), nonadecyl methacrylate, eicosyl methacrylate, behenyl methacrylate and mixtures thereof. Also a mixture of cetyl-eicosyl methacrylate (CEMA), hexadecyl, octadecyl, and eicosyl methacrylate, and a mixture of cetyl-stearyl methacrylate (SMA), hexadecyl and octadecyl methacrylate useful. Preferred high-cut alkyl methacrylates are cetyl-eicosyl methacrylate and cetyl-stearyl methacrylate.

The mid-cut and high-cut alkyl (meth) acrylate monomers described above are generally prepared by standard esterification processes using long-chain aliphatic alcohols of technical grade, and these commercially available alcohols have from 10 to 10 carbon atoms in the alkyl group. 15 or 16 to 20, a mixture of alcohols with varying chain lengths. As a result, for the purposes of the present invention, alkyl (meth) acrylates may be combined with the named individual alkyl (meth) acrylate products, as well as the amount of the named specific alkyl (meth) acrylates predominant with the alkyl (meth) acrylates. It contains a mixture of. The use of these commercially available alcohol mixtures to produce (meth) acrylate esters results in the LMA, DPMA, SMA and CEMA monomer forms described above. Preferred (meth) acrylic acid derivatives useful in the process of the present invention are methyl methacrylate, butyl methacrylate, isodecyl methacrylate, lauryl-myristyl methacrylate, dodecyl-pentadecyl methacrylate, cetyl-eico Sil methacrylate and cetyl-stearyl methacrylate.

For the purposes of the present invention, copolymer compositions exhibiting the blending of monomers from the aforementioned classes of monomers can be prepared using the methods of the present invention. For example, copolymers of alkyl (meth) acrylate monomers with vinylaromatic monomers such as styrene, alkyl (meth) acrylate monomers and substituted (meth) s such as N, N-dimethylaminopropyl methacrylamide Copolymers of acrylamide monomers, copolymers of alkyl (meth) acrylate monomers with monomers based on nitrogen-containing ring compounds such as N-vinylpyrrolidone, air with vinyl acetate and fumaric acid and derivatives thereof Copolymers and copolymers of (meth) acrylic acid and derivatives thereof with maleic acid and derivatives thereof.

The process of the present invention provides a means for preparing a mixture of multiple copolymer compositions in a single operation by controlling the introduction of individual monomers or monomer forms into the polymerization medium during polymerization. As used herein, a “monomer type” refers to a monomer that represents a mixture of closely related related monomers, such as LMA (a mixture of lauryl and myristyl methacrylate), DPMA (dodecyl, tridecyl). , A mixture of tetradecyl and pentadecyl methacrylate), SMA (mixture of hexadecyl and octadecyl methacrylate), CEMA (mixture of hexadecyl, octadecyl and eicosyl methacrylate). For the purposes of the present invention, when expressing monomer proportions and copolymer composition, each such mixture represents a single monomer or “monomer form”. For example, it is understood that a copolymer contains at least 5 different individual monomers (lauryl, myristyl, hexadecyl, octadecyl and ecosyl methacrylate), but the air described as having a 70/30 LMA / CEMA composition. The coalescence is thought to contain 70% of the first monomer or monomer form (LMA) and 30% of the second monomer or monomer form (CEMA).

Lubricant additives such as pour point depressants, thickeners, viscosity index (VI) improvers and dispersants can be prepared using the process of the invention. In this case, methyl methacrylate, butyl methacrylate, isodecyl methacrylate, lauryl-myristyl methacrylate, dodecyl-pentadecyl methacrylate, cetyl-ecosyl methacrylate and cetyl-stearyl Preference is given to continuous variable-composition copolymers comprising a single-composition copolymer having monomeric units selected from at least two of the methacrylates. Preferably, the continuous variable-composition copolymer used as lubricant additive has an overall average composition of 40-90% X and 10-60% Y and preferably 50-70% X and 30-50% Y, where X Is a monomeric unit selected from one or more of isodecyl methacrylate (IDMA), lauryl-myristyl methacrylate (LMA) and dodecyl-pentadecyl methacrylate (DPMA), and Y is cetyl-eicosyl meta Monomeric units selected from one or more of methacrylate (CEMA) and cetyl-stearyl methacrylate (SMA). Preferably, the monomeric unit composition range of the single-component copolymer in the continuous variable-composition copolymer used as the lubricating oil additive is 5 to 100%, preferably 10 to 10, for at least one of the monomeric unit components X or Y. 80%, more preferably 20 to 50%, most preferably 30 to 40%. For example, using the same definitions for the X and Y monomeric units as above, the continuous variable-composition copolymer can be from 10 LMA / 90 SMA copolymer to 90 LMA / 10 SMA copolymer (80% range) or 25 LMA / 75 SHA copolymer to 75 LMA / 25 SMA copolymer (50% range) or 30 LMA / 70 SMA copolymer to 30 LMA / 70 SMA copolymer (40% range), each continuous-variable composition The overall average composition is 50 LMA / 50 SMA. The monomeric unit composition range need not be symmetric in the overall average composition of the continuously-variable composition copolymer.

A preferred application of this technique is the preparation of VI improver additives that provide improved VI and low temperature performance by allowing the use of large amounts of low-solubility monomers such as methyl methacrylate in polymer additives. Another preferred application of this technique is the preparation of polymeric pour point depressant additives which provide improved low temperature fluidity when used in various petroleum oils. Generally, a low temperature means a temperature below about -20 ° C (corresponding to -4 ° F), and fluidity at temperatures below about -25 ° C (corresponding to -13 ° F) means the use of a pour point depressant additive. I am particularly interested in

When the process of the invention is used to prepare lubricant additives, the typical maximum [X _i -X _T ] or [Y _i -Y _T ] absolute value used during the polymerization is from 5 to 100%, preferably from 10 to 80 %, More preferably 20 to 50%. For example, pour point depressant additives based on prepared variable-composition copolymers, where [X _i -X _T ] or [Y _i -Y _T ] values are 30 to 40%) are used in a wide range of base oils Preferred below.

The copolymers produced by the process of the present invention provide broader applicability in the treatment of base oils from different raw materials when compared to a combination of single-component polymer additives or separately prepared single-component polymer additives. In some cases, the continuously-variable composition copolymers of the present invention equal or exceed the low temperature performance of comparable single-composition polymer additives or mixtures thereof. In all cases, continuously-variable composition copolymers offer the advantage of being widely applicable to different base oils without the need of separately preparing and then blending different single composition polymers to obtain satisfactory performance in various base oils.

The process of the present invention is used to prepare continuous-variable composition copolymers by semi-batch or semi-continuous methods. As used herein, semi-batch means a method in which the reactants are added to the polymerization reactor, one or more of them are added over the course of the reaction, and after the polymerization is complete the finished copolymer is removed to the final product. Batch polymerization refers to a process in which all of the reactants are initially added to the reactor and after the polymerization is complete the finished polymer is removed as the final product. Continuous polymerization is a process in which all reactants (in a constant relationship) are added to the reactor continuously and the polymer-reactant stream is continuously removed at the same rate as the reactants are added. As used herein, semi-continuous, for example, the resulting polymer-reactant mixture of each continuous reactor is continuously fed to the next reactor, each continuous reactor having a monomer ratio (e.g., step function, saw tooth vibration), By means of a continuous-mode reactor that can use different sets of conditions indicating monomer feed rate, initiator ratio to monomer, or change in initiator feed rate, it is possible to continuously connect, resulting from a series of last reactors The polymer product is similar to the polymer produced by operating one reactor in semi-batch mode. Among the reactor types useful in the practice of the present invention are, for example, pipe (plug flow), regenerated-loop and continuous-feed-stirred tank (CFSTR) type reactors.

The process of the invention can be done as a cofeed or heel method, with a combination of cofeed-heel methods being preferred. The co-feed method is a method of metering or feeding the major portion of the reactants into the reactor over a period of time. When using a co-feed method, the initiator and monomer can be introduced into the reaction mixture as separate streams or mixtures which can be fed linearly, ie at a constant rate or at a variable rate. The streams are arranged so that one or more of the streams are fed completely before the other. The monomers can be supplied as separate streams to the reaction mixture or combined in one or more streams. The Hill method is where some portion of one or more reactants or diluents are present in the polymerization reactor, and the reactants and diluent remaining at a later point in time are added to the reactor. The combination of Hill and co-feeding methods allows one or more reactants or portions of diluent to be present in the polymerization reactor, and the remaining one or more reactants or dilutions are metered (including changes in the individual monomer feed rates) or feed into the reactor over time. That's how.

The process of the present invention is applicable to the preparation of copolymers by bulk or solution polymerization techniques. When the initiator feed from the continuous phase (usually aqueous system) is suitably converted to suspension or emulsion particles or dispersed phase (usually water-insoluble) so that the copolymer composition is actually represented by the composition of the monomer feed entering the polymerization reactor. , Suspension and emulsion polymerization processes can also benefit from the process of the invention.

The process of the invention is particularly applicable to the preparation of polymers by solution (aqueous or solvent) polymerization. Preferably, the process of the present invention is applied to solution (solvent) polymerization by mixing selected monomers in the presence of a polymerization initiator, a diluent and a chain transfer agent.

Generally, when higher temperatures are used, the polymerization can be carried out under pressure, but the polymerization temperature is below the boiling point of the system, for example, about 60 to 150 ° C., preferably 85 to 130 ° C., more preferably 110 To 120 ° C. Polymerization (including monomer feed and retention times) is usually about 4 to 10 hours, preferably 2 to 3 hours, or up to the desired degree of polymerization, eg, at least 90%, preferably 95%, in the copolymerizable monomer Or more, more preferably, at least 97% until conversion to the copolymer. As will be appreciated by those skilled in the art, the reaction time and temperature will vary depending on the choice of initiator and the target molecular weight.

When the process of the invention is used for solvent (non-aqueous) polymerization, suitable initiators for use include, for example, acetyl peroxide, benzoyl peroxide, lauroyl peroxide, tert-butyl peroxyisobutyrate, Caproyl peroxide, cumene hydroperoxide, 1,1-di (tert-butylperoxy) -3,3,5-trimethylcyclohexane, azobisisobutyronitrile and tert-butyl peroctoate (3 One of the well-known free-radical-producing compounds, such as peroxy, hydroperoxy and azo initiators, also known as quat-butylperoxy-2-ethylhexanoate. The initiator concentration is typically 0.025 to 1% by weight, preferably 0.05 to 0.5% by weight, more preferably 0.1 to 0.4% by weight and most preferably 0.2 to 0.3% by weight based on the total weight of the monomers. In addition to the initiator, one or more promoters may also be used. Suitable promoters include, for example, quaternary ammonium salts such as benzyl (hydrogenated-tallow) -dimethylammonium chloride and amines. Preferably, the promoter is soluble in hydrocarbons. If used, the promoter is present at a level of about 1 to 50%, preferably about 5 to 25%, based on the total weight of the initiator. Chain transfer agents may also be added to the polymerization reaction to control the molecular weight of the polymer. Preferred chain transfer agents are alkyl mercaptans such as lauryl mercaptan (also known as dodecyl mercaptan, DDM) and the concentration of chain transfer agent used is 0 to about 2% by weight, preferably 0 to 1% by weight. to be.

When the process of the invention is used for aqueous phase polymerization, suitable initiators for use are conventional water soluble free-radical initiators and redox redox couples. Suitable free-radical initiators include, for example, peroxides, persulfates, peresters and azo initiators. Mixed initiator systems (redox couples) can also be used, such as combinations of free radical initiators and reducing agents. Suitable reducing agents include, for example, sodium bisulfite, sodium sulfite, hypophosphite, isoascorbic acid and sodium formaldehyde-sulfoxylate. The level of initiator is typically 0.1 to 20% based on the total weight of the polymerizable monomer. Preferably, the initiator is present at a level of 1 to 15%, most preferably 2 to 10%, based on the total weight of the polymerizable monomer. In addition to the initiator, one or more promoters may be used. Suitable promoters include water soluble salts of metal ions. Suitable metal ions include iron, copper, cobalt, manganese, vanadium and nickel. Preferably, the promoter is a water soluble salt of iron or copper. If used, the promoter is present at a level of about 1 to about 100 ppm based on the total weight of the polymerizable monomer. Preferably, the promoter is present at a level of about 3 ppm to about 20 ppm based on the total polymerizable monomer. In particular, when using thermal initiators such as persulfate salts, it is usually desirable to adjust the pH of the polymerization monomer mixture in aqueous phase polymerization. The pH of the polymerization monomer mixture can be adjusted by a buffer system or by the addition of a suitable acid or base, wherein the pH of the system is about 3 to about 10, preferably about 4 to about 8, more preferably about 4 to about 6.5 Is maintained. Similarly, when using redox couples there will be an optimal pH at which to perform the polymerization depending on the choice of the components of the redox couple. The pH of the system can be adjusted to the choice of redox couple by adding an effective amount of a suitable acid or base. Conventional water soluble chain regulators or chain transfer agents can be used to control the molecular weight in aqueous phase polymerizations. Suitable chain modifiers are, for example, mercaptans (eg 2-mercaptoethanol and 3-mercaptopropionic acid), hypophosphites, phosphites (such as sodium phosphite), isoascorbic acid, alcohols, aldehydes, hyposulfur Pit and bisulfite, such as sodium metabisulfite.

When the polymerization is carried out in solution polymerization using a solvent other than water, the reaction can be up to about 100% by weight of the polymerizable monomer (when the formed polymer behaves as a solvent itself) or about 70% by weight, based on the total reaction mixture. Hereinafter, preferably 40 to 60% by weight. Similarly, when the polymerization is carried out by aqueous polymerization, the reaction should be carried out at about 70% by weight or less, preferably 40 to 60% by weight, based on the total reaction mixture. The solvent or water, if used, may be introduced into the reaction vessel by heel charging or fed to the reactor as a separate feed stream or as a diluent for one of the other components to be fed to the reactor.

Diluents can be added to the monomer mixture or to the reactor with the monomer feed. Diluents may also be used to provide a solvent heel, preferably a non-reactive solvent heel, for polymerization, in which case the monomer and initiator feed are mixed well, especially at the beginning of the polymerization. It is added to the reactor before the initiator feed is commenced to provide a suitable volume of liquid to the reactor. Preferably, the material chosen as the diluent should be actually non-reactive to the initiator or intermediate in the polymerization to minimize side reactions such as chain transfer and the like. The diluent may also be a polymeric material that acts as a solvent or may be miscible with the monomers and polymerization components used.

Among the diluents suitable for use in the process of the present invention for non-aqueous solution polymerization are aromatic hydrocarbons such as benzene, toluene, xylene and aromatic naphtha, chlorinated hydrocarbons such as ethylene dichloride, chlorobenzene and dichlorobenzene, esters (E.g. ethyl propionate or butyl acetate), (C ₆ -C ₂₀ ) aliphatic hydrocarbons (e.g. cyclohexane, heptane and octane), petroleum oils (e.g. paraffinic and naphthalene oils) or synthetic oils [e.g. Olefin copolymer (OCP) lubricants such as poly (ethylene-propylene) or poly (isobutylene). When blending the concentrate directly to lubricating oils, more preferred diluents are mineral oils, such as 100 to 150 neutral oils (100N or 150N oils), which are miscible with the final lubricating oil.

In the preparation of lubricant additive polymers, the resulting polymer solution usually has a polymer content of about 50 to 95% by weight after polymerization. The polymer can be separated and used directly in the lubricant formulation or the polymer-diluent solution can be used in the form of a concentrate. When used in concentrate form, the polymer concentration can be adjusted to the desired level with additional diluent. Preferred polymer concentrations in the concentrate are 30 to 70% by weight. When adding a polymer prepared by the process of the invention to a base oil fluid, whether as a pure polymer or as a concentrate, the final concentration of the polymer in the blended fluid is typically from 0.05 to 20, depending on the particular use application requirements. %, Preferably 0.2 to 15%, more preferably 2 to 10%. For example, when continuous variable-composition copolymers are used, for example, as pour point depressants, to maintain low temperature fluidity in lubricating oils, the final concentration of the continuous variable-composition copolymer in the blended fluid is typically from 0.05 to 3%, preferably 0.1 to 2%, more preferably 0.1 to 1%, and when the continuous variable-composition copolymer is used as a VI improver in lubricating oils, the final concentration in the blended fluid is typically 1 to 6 %, Preferably 2 to 5%, and when the continuous variable-composition copolymer is used as a hydraulic fluid additive, the final concentration in the blended fluid is usually 5 to 15%, preferably 3 to 10%.

The weight-average molecular weight (Mw) of the polymers produced by the process of the invention is between 5,000 and 2,000,000. The weight-average molecular weight of alkyl (meth) acrylate polymers useful as lubricating oil additives is 10,000 to 1,000,000. As the weight-average molecular weight of the polymer increases, it becomes a more effective thickener. However, in certain applications they are mechanically degraded and for this reason, polymer additives with Mw greater than about 500,000 are not suitable because they are deteriorated by molecular weight degradation resulting in loss of efficacy as thickener at higher service temperatures (eg 100 ° C.). Tend to "thinning". Thus, the desired Mw ultimately depends on the thickening effect, cost and application form. Typically, the polymeric pour point depressant additive of the present invention has a Mw of about 30,000 to about 700,000 [measured by gel permeation chromatography (GPC) using poly (alkylmethacrylate) standards], and preferably the pour point depressant Mw is in the range of 60,000 to 350,000 to satisfy the particular use as. The weight-average molecular weight is preferably 70,000 to 300,000.

The polydispersity index of the polymers produced by the process of the invention is 1 to about 15, preferably 1.5 to about 4. Polydispersity (Mw / Mn, measured by GPC, Mn is the number-average molecular weight) is a measure of the narrowness of the molecular weight distribution, with higher values showing an increasingly wider distribution. For polymers used as VI improvers in crankcase and hydraulic fluid applications, the molecular weight distribution is preferably as narrow as possible, but usually limited by the method of preparation. Some approaches for providing a narrow molecular weight distribution (low Mw / Mn) include, for example, one or more of the following methods. Anionic polymerization, continuous-feed-stirred-tank-reactor (CFSTR), low-conversion polymerization, control of temperature or initiator / monomer ratio during polymerization (e.g., European Patent Publication No. 561078 to achieve a constant degree of polymerization) And mechanical shearing of polymers, for example homogenization.

Those skilled in the art are described throughout this specification. It will be appreciated that the molecular weight is related to the measurement method. For example, the molecular weight measured by GPC and the molecular weight calculated by another method may have different values. What matters is not the molecular weight as such but the handling characteristics and performance (shear stability and thickening force under the conditions of use) of the polymeric additive. Typically, shear stability is inversely proportional to molecular weight. In order to achieve the same target thickening effect in fluids treated at high temperatures, VI improving additives with better shear stability (lower SSI values) than other additives with reduced shear stability (high SSI values, see below) are usually present at high initial concentrations. use. However, additives with good shear stability exhibit unacceptable thickening at low temperatures because of the high concentrations of use.

Thus, the polymer composition, molecular weight and shear stability of the pour point depressant and VI improving additive used to treat different fluids should be chosen to balance properties to meet both high and low temperature performance requirements.

Shear stability (SSI) is a measure of percent loss in viscosity due to polymeric additives by mechanical shear and can be directly related to polymer molecular weight, for example, ASTMD-2603-91 [American Society of Test and Materials]. for testing and materials) can be determined by measuring the sonic shear stability for a given time. Depending on the final application of the lubricant, the viscosity is measured before and after shearing for a specified time to determine the SSI value. In general, high molecular weight polymers also exhibit maximum SSI values, since the high molecular weight polymers have a maximum relative decrease in molecular weight when performed at high shear conditions. Therefore, when comparing the shear stability of polymers, good shear stability is associated with lower SSI values and reduced shear stability is associated with higher SSI values.

The SSI range for the alkyl (meth) acrylate polymers useful as lubricant additives (e.g. VI improvers, thickeners, pour point depressants, dispersants) prepared by the process of the present invention is from about 0 to about 60%, preferably 1 to 40 %, More preferably 5 to 30% and will vary depending on the final application. SSI values are usually expressed as integers, even if they are%. The desired SSI for the polymer can be achieved by changing the synthetic reaction conditions or mechanically shearing the product polymer of known molecular weight to the desired value.

Representative of the shear stability forms measured in conventional lubricant additives with different Mw are as follows: Conventional poly (methacrylate) additives with Mw of 130,000, 490,000 and 880,000, respectively, are based on a 2000 mile rod shear test on an engine oil formulation. The SSI values (210 ° F) are 0%, 5% and 20%, respectively, and the SSI values (210 ° F) are 0% and 35%, respectively, based on a 20,000 mile high-speed load test for the Automatic Transmission Fluid (ATF) formulation. And 50%, based on a 100 hour ASTM D-2882-90 pump test on hydroponic fluids, SSI values (100 ° F.) are 18%, 68% and 76%, respectively. See Effect of Viscosity Index Improver on In. -Service Viscosity of Hydraulic Fluids, RJ Kopko and RL Stambaugh, Fuel and Lubricants Meeting, Houston, Texas, June 3-5, 1975, Society of Automotive Engineers).

The pumping capacity of oil at low temperatures, as measured by a mini-rotary viscometer (MRV), is related to the viscosity under low shear conditions at engine start-up. Since the MRV test is a measure of pump capacity, the engine oil must be fluid enough to be pumped to all engine parts after engine start to provide adequate lubrication. ASTM D-4684-89 covers viscosity measurements in the temperature range of -10 to -30 ° C and describes the TP-1 MRV test. The SAE J300 engine oil viscosity classification (December 1995) allows up to 30 pa.sec or 300 poise at -30 ° C for SAE 5W-30 oil using the ASTM D-4684-89 test procedure. Another aspect of the low temperature performance measured by the TP-1 MRV test is yield stress (recorded in pascals), with values below 35 pascals (the sensitivity limit of the plant) recorded as "0" yield stress, but the target value for yield stress is " 0 "pascal. Yield stress values in excess of 35 pascals indicate a less desirable increase in performance.

Tables 1, 3 and 4 show viscosity data (cold pump capability) for polymeric additives prepared by the process of the present invention compared to conventional polymer additives (single-composition polymers or physical mixtures of two different single-composition polymers). Useful for performance prediction). The data in the table is the corresponding viscosity and yield stress values at low temperatures selected for blended oils that differ from the throughput (weight percent of polymer additives in the blended oil). Base oils A and B are representative oils from the catalyst dewaxing method and the solvent extraction dewaxing method, respectively, and each base oil is formulated with a viscosity standard of grades 10W-40 and 5W-30, respectively. Base oils A and B represent oils of greatly different form for the expected ease of meeting target viscosity standards for formulated oils, where base oil A is a “hard to handle” oil and base oil B is “easy to handle”. Indicates oil. Base oils A and B are used as part of a screening method to identify and distinguish polymeric additives with respect to their relative ability to most closely meet the TP-1 MRV standard of both A and B oils. Low viscosity (less than 30 pa.sec) and 0 pascal yield stress values represent the desired target performance.

In Table 1, Polymer # 14C represents a single-composition copolymer additive based on 70 LMA / 30 SMA and can be most directly compared to Polymer # 4 of the present invention for low temperature performance: two polymers are based oil A Performs similarly at and # 4 shows slightly improved performance in base oil B compared to # 4C. Polymers 12C and 13C, respectively, represent a physical mixture of conventional single-composition (48 LMA / 52 CEMA) and two single-composition additives (total average of 50 LMA / (35 SMA + 15 CEMA), and for low temperature performance Most directly comparable to polymers # 3, # 5, # 6, # 9, # 10 and # 11 of the two polymer groups performing similarly in base oil A and compared to conventional polymers # 3, # 6 And # 9 show improved performance, perform similarly in base oil B and two groups of polymers show improved performance of # 11 compared to conventional polymers Polymers # 3, # compared to low throughput (0.06%) High throughputs (0.18% and 0.36%) for 9, # 10 and # 11 show correspondingly improved performance.

In addition to base oils A and B, commercial oils C and D (two different viscosity grades each) are also used to assess pump capacity performance. The properties of the untreated commercial oils C and D are shown below: Pour point according to ASTM D 97 (indicative of the ability to remain fluid at very low temperatures and expressed as the temperature when the oil no longer flows), viscosity Index (VI), Kinetic and Dynamic (ASTM D 5293) Bulk Viscosity Characteristics.

In Table 3, conventional single-composition copolymer additives (# 14C) or mixed conventional additive combinations (# 15 and # 16C) are compared with polymer # 17 containing the continuously-variable compositional copolymers of the present invention. Whereas conventional additives or additive mixtures showed inconsistent results in commercial oil C formulations, polymer # 17 performed well in both variants of commercial oil C.

In Table 4, conventional additive formulations mixed with the conventional single-composition copolymer additives as shown in Table 3 are compared to Polymer # 17 using a commercial Oil D formulation. Again, while conventional additives or additive mixtures showed inconsistent results in commercial oil D formulations, # 17 performed well in both variants of commercial oil D.

Another measure of the low temperature performance of the formulated oil, called Injection Brookfield Viscosity (ASTM 5133), measures the lowest temperature achievable by the oil formulation before the viscosity exceeds 30.Opa.sec (or 300 poise). Formulated oils with low "30 pa.sec temperature" values are expected to maintain flowability at lower temperatures more easily than other blended oils with high "30 pa.sec temperature" values, and target values for oils of different viscosity grades are SAE. Less than -30 ° C for 5W-30 blended oil, less than -25 ° C for SAE 10W-40 blended oil, less than -20 ° C for SAE 15W-40 blended oil and SAE 20W-50 blended oil Less than -15 ° C. Another aspect of low temperature performance as measured by ASTM 5133 is a dimensionless scale (typically 3 to 3) indicating the tendency of formulated oils to "gel" or "setup" as a function of decreasing temperature profile at low temperature conditions. Gel index, based on 100 ranges). Low gel index values show good cold flow and target values are less than about 8-12 units.

Tables 2, 5 and 6 show injection Brookfield viscosity performance data for polymeric additives prepared by the method of the present invention compared to conventional polymer additives (single-composition polymers or physical mixtures of two different single-composition copolymers). Indicated. The data in the table are the corresponding "30 pa.sec temperature" and gel index values in the blended oil that differ from the throughput (weight percent of the polymer additive in the blended oil). Low "30a sec temperature" and low gel index values (less than 8-12 units) indicate the desired target performance.

In Table 2, polymers 12C and 13C each represent a physical mixture of conventional single-composition (48 LMA / 52 CEMA) and two single-composition additives with an overall average of 50 LMA / (35 SMA + 15 CEMA), It is directly comparable to polymers # 3, # 9, # 10 and # 11 (with similar overall "average" polymer composition) of the present invention for low temperature performance: two polymer groups perform similarly in base oils A and B # 3 shows slightly improved performance compared to conventional polymers in base oil A, with high throughputs for polymers # 3, # 9, # 10 and # 11 (0.18% and 0.36) compared to low throughput (0.06%). %) Shows a correspondingly improved performance.

In Tables 5 and 6, conventional single-composition copolymer additives (# 14C) or mixed conventional additive combinations (# 15C and # 16C) contain polymer # 17, containing the continuously-variable composition copolymer of the present invention. Compare. Whereas conventional additives or additive mixtures exhibit inferior performance in commercial oils C and D, polymer # 17 performs well in both variants of commercial oils C and D.

The abbreviations used in the examples and tables are listed below with corresponding descriptions, and the polymer additive compositions are expressed in relative proportions of the monomers used. Polymer Example Identification Number (Ex #) followed by "C" means a comparative example that is not within the scope of the present invention: Examples 1-11 and 17 refer to copolymers prepared by the process of the present invention. Examples 12-16 show conventional polymers or conventional polymer mixtures for comparison purposes.

MMA = Methyl Methacrylate

LMA = lauryl-myristyl methacrylate mixture

IDMA = Isodecyl methacrylate

DPMA = dodecyl-pentadecyl methacrylate mixture

SMA = cetyl-stearyl methacrylate mixture

CEMA = cetyl-eicosyl methacrylate mixture

HPMA = hydroxypropyl methacrylate

DDM = dodecyl mercaptan

SSI = shear stability

NM = not measured

TABLE 1

TABLE 2

TABLE 3

TABLE 4

TABLE 5

TABLE 6

Table 7 summarizes the process parameters used to make the copolymers using the method of the present invention. The overall average composition refers to the final copolymer composition based on the total amount of X and Y monomers used during the polymerization, and the range for the X monomers to represent the single-composition copolymer composition width in each of the continuously-variable copolymers prepared. It is provided. For example, polymers # 9, # 10 and # 11 all exhibit 50X / 50Y continuous variable-composition copolymers, but each was made with significantly different parameters within the scope of the method of the present invention. Table 7A shows data for initial X and Y monomer concentrations in the reactor and the maximum difference in X and Y monomer component concentrations during polymerization. Conventional polymer # 12C is included in Tables 7 and 7A to show process parameter control for polymers # 1 to # 11. For example, polymers # 12C have a maximum of [X _i -X _T ] or [Y _i , while polymers # 1 to # 11 have a [X _i -X _T ] or [Y _i -Y _T ] range of 10 to 100. -Y _T ] The value is "0".

TABLE 7

TABLE 7a

Some aspects of the invention are described in more detail in the Examples below. Unless otherwise indicated, all ratios, parts and percentages are by weight, and unless otherwise indicated, all used reagents have good commercial quality. Examples 1-11 provide information on preparing polymers using the process of the invention and Tables 1-6 provide performance data on lubricant blends containing polymers.

Example 1 Preparation of Pour Point Depressant 1

A nitrogen-washed reactor is charged with 160 parts of 100N polymer oil (bromine number less than 12). The oil is heated to 120 ° C., the desired polymerization temperature. Prepare two separate monomer mixtures: Mixture 1 is placed in a stirred addition vessel containing 574.36 parts of LMA (70%), 248.7 parts of SMA (30%) and 64 parts of 100N polymerization oil and connected to the polymerization reactor by a transfer line, Mixture 2 consists of 820.51 parts of LMA (100%) and 64 parts of 100N polymer oil. Mixture 2 is pumped to a stirred addition vessel containing mixture 1 at a rate exactly the same as the rate of pumping the contents of the addition vessel to the reactor. At the same time as pumping the monomer mixture into the polymerization reactor and the stirred addition vessel, a solution of tert-butyl peroctoate initiator (20% in 100N polymerization oil) is fed to the reactor at a rate calculated to have a degree of polymerization of 200 (see European Patent Publication No. 561078). After 90 minutes both monomer mixtures 2 are pumped to the addition vessel containing mixture 1 to terminate the monomer feed to the reactor. About 810 parts of the monomer mixture are added to the reactor. The monomer mixture (about 90 LMA / 10 SMA) remaining in the addition vessel is retained for use as the monomer mixture in a separate polymerization (or some or all of the remaining monomer mixture can be added to the reactor, in which case the final The polymer consists of about 10-50% of a 90 LMA / 10 SMA single-composition copolymer and about 50-90% of a 70 LMA / 30 SMA → 90 LMA / 10 SMA continuous variable-composition copolymer). The initiator feed is continued for an additional 90 minutes, with the calculated conversion being 97% and the total amount of initiator solution fed is 36.2 ml. The reaction solution is stirred for an additional 30 minutes and then additional 200 parts of 100N polymer oil is added, further mixed for 30 minutes and then transferred from the reactor. The product contains 60.6% polymer solids, indicating a 96.6% conversion of monomer to polymer. The composition of the material formed begins with 70% LMA, 30% SMA and ends with about 90% LMA, 10% SMA.

Example 2 Preparation of Pour Point Depressant 2

A pour point depressant polymer solution is prepared in a similar manner to that described in Example 1, except for the following. Monomer Mixture 1 contains 738.46 parts of LMA (90%), 82.9 parts of SMA (10%) and 64 parts of 100N polymer oil, Mixture 2 contains 492.31 parts of LMA (60%), 331.61 parts of SMA (40%) and 100N polymer oil It contains 64 parts. The remaining monomer mixture (about 70 LMA / 30 SMA) in the addition vessel is maintained for use as monomer mixture in a separate polymerization. The initiator feed amount is 37.7 ml and the conversion calculated at the end of the initiator feed is 97%. The product contains 60.1% of polymer solids, indicating a 95.9% conversion of monomer to polymer. The composition of the material formed begins with 90% LMA, 10% SMA and ends with about 70% LMA, 30% SMA.

Example 3 Preparation of Pour Point Depressant 3

A nitrogen-washed reactor is charged with 160 parts of 100N polymer oil (bromine number less than 12). The oil is heated to 115 ° C., the desired polymerization temperature. Prepare two separate monomer mixtures: Mixture 1 contains 123.08 parts of LMA (30%), 290.16 parts of SMA (70%), 2.20 parts of DDM and 1.16 parts of tert-butyl peroctoate solution (in odorless inorganic spirits). 50%) and placed in a stirred addition vessel connected to the polymerization reactor by transmission line, mixture 2 contains 287.18 parts of LMA (70%), 124.35 parts of SMA (30%), 2,20 parts of DDM and tert-butyl perocto It contains 1.16 parts of an acid solution (50% in odorless inorganic spirits). Mixture 2 is pumped to a stirred addition vessel containing mixture 1 at exactly half the rate of pumping the contents of the addition vessel into the reactor. No initiator is added separately to the reactor. It takes 90 minutes to complete the monomer feed. The reactor contents are held for an additional 30 minutes at 115 ° C. and then a solution of 2 parts of a tert-butyl peroctoate solution (50% in an odorless inorganic spirit) in 80 parts of 100N polymer oil is added over 60 minutes. The reaction solution is stirred for an additional 30 minutes and then 219 parts of 100N polymer oil is added, mixed for an additional 30 minutes and then transferred from the reactor. The product contains 61.2% polymer solids, indicating a 98.8% conversion from monomer to polymer. The composition of the material formed begins at 30% LMA, 70% SMA and ends at about 70% LMA, 30% SMA. The polymer has a Mn of 30,300.

Example 4 Preparation of Pour Point Depressant 4

A pour point depressant polymer solution is prepared in a similar manner to the method described in Example 3 except for the following. Monomer mixture 1 contains 225.64 parts of LMA (55%), 186.53 parts of SMA (45%), 2.20 parts of DDM and 1.16 parts of tert-butyl peroctoate solution (50% in odorless inorganic spirits), mixture 2 348.72 parts LMA (85%), 62.18 parts SMA (15%), 2.20 parts DDM and 1.16 parts tert-butyl peroctoate solution (50% in odorless inorganic spirit) and 64 parts 100N polymer oil. The product contains 60.6% of polymer solids, indicating a 97.9% conversion of monomers to polymers. The composition of the material formed begins with 55% LMA, 45% SMA and ends with about 85% LMA, 15% SMA.

Example 5 Preparation of Pour Point Depressant 5

Prepare five separate monomer mixtures: Mixture 1 contains 30,77 parts of LMA (30%), 72.74 parts of SMA (70%), tert-butyl peroctoate solution (50% in odorless inorganic spirit) 0.3 Parts and 0.55 parts of DDM, Mixture 2 contains 41.03 parts of LMA (40%), 62.18 parts of SMA (60%), 0.3 parts of tert-butyl peroctoate solution (50% in odorless inorganic spirits) and DDM 0.55 Part 3, Mixture 3 contains 51.28 parts LMA (50%), 51.58 parts SMA (50%), 0.3 parts tert-butyl peroctoate solution (50% in odorless inorganic spirit) and 0.55 parts DBM, Mixture 4 contains 61.54 parts of LMA (60%), 41.45 parts of SMA (40%), 0.3 parts of tert-butyl peroctoate solution (50% in odorless inorganic spirits) and 0.55 parts of DDM, and mixture 5 contains LMA (70%) 71.79 parts, SMA (30%) 30.09 parts, tert-butyl peroctoate solution (50% in odorless inorganic spirit) and 0.55 parts DDM. 100 parts of mixture 1 and 100N polymerization oil (bromine number less than 12) are added to a nitrogen-washed polymerization reactor and heated to 115 ° C. The reactor contents are held at this temperature for 10 minutes and then mixture 2 is added quickly. The reactor contents were held at 115 ° C. for 15 minutes, then Mixture 3 was added and again maintained for 15 minutes, Mixture 4 was added, followed by another 15 minutes, then Mixture 5 was added and then again 15 minutes Keep it on. It takes about 5 minutes to add each monomer mixture. After holding for the last 15 minutes, 1.25 parts of tert-butyl peroctoate solution (50% in odorless inorganic spirit) in 50 parts of 100N polymer oil are added at a uniform rate over 50 minutes. The reaction solution is stirred for 15 minutes, then diluted with 135 parts of 100N polymerization oil and mixed for an additional 15 minutes, after which the reaction solution is transferred from the reactor. The product contains 60.1% of polymer solids, indicating a 96.9% conversion of monomers to polymers.

Example 6 Preparation of Pour Point Depressant 6

Prepare nine separate monomer mixtures: Mixture 1 contains 17,1 parts of LMA (30%), 40.3 parts of SMA (70%), tert-butyl peroctoate solution (50% in odorless inorganic spirit) 0.17 Parts and 0.3 parts of DDM, Mixture 2 contains 19.94 parts of LMA (35%), 37.42 parts of SMA (65%), 0.17 parts of tert-butyl peroctoate solution (50% in odorless inorganic spirit) and DDM 0.3 Part 3, Mixture 3 contains 22.79 parts LMA (40%), 34.55 parts SMA (60%), 0.17 parts tert-butyl peroctoate solution (50% in odorless inorganic spirit) and 0.3 parts DDM, Mixture 4 contains 25.64 parts of LMA (45%), 31.67 parts of SMA (55%), 0.17 parts of tert-butyl peroctoate solution (50% in odorless inorganic spirits) and 0.3 parts of DDM, and mixture 5 contains LMA (50%) 28.49 parts, SMA (60%) 28.79 parts, tert-butyl peroctoate solution (50% in odorless inorganic spirits), 0.17 parts and 0.3 parts of DDM; mixture 6 contains LMA (55%) 31.34 parts, SMA (45%) 25.91 parts, tert-butyl peroctoate solution (odorless 50%) in inorganic spirits of 0.17 parts and 0.3 parts of DDM, mixture 7 contains 34.19 parts of LMA (60%), 23.03 parts of SMA (40%), tert-butyl peroctoate solution (odorless inorganic spirits) 50%) in 0.17 parts and DDM 0.3 parts, mixture 8 contains 37.04 parts LMA (65%), 20.15 parts SMA (35%), tert-butyl peroctoate solution (50% in odorless inorganic spirit) 0.17 parts and 0.3 parts of DDM; mixture 9 contains 39.89 parts of LMA (70%), 17.27 parts of SMA (30%), 0.17 parts of tert-butyl peroctoate solution (50% in odorless inorganic spirit) and DDH It contains 0.3 part. 100 parts of mixture 1 and 100N polymerization oil (bromine number less than 12) are added to a nitrogen-washed polymerization reactor and heated to 115 ° C. The reactor contents are held at this temperature for 10 minutes and then mixture 2 is added quickly. The reactor contents are held at 115 ° C. for 15 minutes, then the respective mixtures (3 to 9) are added and then each for another 15 minutes. Each monomer mixture addition takes about 5 minutes. After holding for the last 15 minutes, 2.0 parts of a tert-butyl peroctoate solution (50% in odorless inorganic spirit) in 50 parts of 100N polymer oil are added at a uniform rate over 50 minutes. The reaction solution is stirred for 15 minutes, then diluted with 135 parts of 100N polymer oil and after a further 15 minutes of mixing, the reaction solution is transferred from the reactor. The product contains 60% polymer solids, which indicates that the conversion from monomer to polymer is 96,8%.

Example 7 Preparation of Dispersant Viscosity Index Improver

The nitrogen-washed reactor is charged with 176 parts of 100N polymer oil (bromine number less than 12), 1.38 parts of a 25% solution of benzyl (hydrogenated-dimethyl) ammonium chloride in mixed butanol and 0.1 parts of cumene hydroperoxide. The oil is heated to 115 ° C., the desired polymerization temperature. Prepare two separate monomer mixtures: Mixture 1 contains 183.67 parts of IDMA (45%), 126.32 parts of CEMA (30%), 80 parts of MMA (20%), 20 parts of HPMA (5%) and 0.32 cumene hydroperoxide Part and placed in a stirred addition vessel connected to the polymerization reactor by transmission line, mixture 2 contains 224.49 parts of IDMA (55%), 126.32 parts of CEMA (30%), 40 parts of MMA (10%), HPMA (5%) 20 Part and 0.32 part cumene hydroperoxide. Mixture 2 is pumped into a stirred addition vessel containing mixture 1 at exactly half the rate of pumping the contents of the addition vessel into the reactor. It takes 90 minutes to complete the monomer feed. The reactor contents were held for an additional 30 minutes at 115 ° C., followed by the addition of a solution of 0.22 parts of cumene hydroperoxide in 6 parts of 100N polymer oil, followed by benzyl (hydrogenated-wood) in mixed butanol in 6 parts of 100N polymer oil. 0.46 parts of a 25% solution of dimethylammonium chloride are added. After 30 minutes, a second pair of initiator solution is added as above, followed by a third pair of initiator solution, which is the same as the first two pairs after 30 minutes. The reaction solution is stirred for an additional 30 minutes, then 600 parts of 100N polymerization oil is added for mixing for an additional 30 minutes and then transferred from the reactor. The product contains 47.0% of polymer solids, indicating a 96.1% conversion from monomer to polymer. The overall average composition of the final polymer is 50% IDMA / 30% CEMA / 15% MMA / 5% HPMA. The SSI of the polymer is 41.3.

Example 8 Preparation of Hydroponic Fluid Viscosity Index Improver

A VI improver polymer solution is prepared in a similar manner to that described in Example 1, except for the following. The polymerization temperature is 115 ° C. Monomer mixture 1 contains 664.62 parts of LMA (80%), 152.23 parts of MMA (20%) and 64 parts of 100N polymer oil, mixture 2 contains 787,69 parts of LMA (96%), 32.5 parts and 100N of MMA (4%). It contains 64 parts of polymerization oil. It takes 93 minutes to feed the monomers. The monomer mixture (about 90 LMA / 10 MMA) remaining in the addition vessel is maintained for use as the monomer mixture in a separate polymerization. Supply of the initiator takes 93 minutes. The initiator feed was 38.0 ml and the conversion calculated at the end of the initiator feed was 97%. The reaction solution is stirred for an additional 30 minutes, then additionally 22.1 parts of 100N polymerization oil is added and further mixed for 30 minutes, after which the reaction solution is transferred from the reactor. The product contains 70.7% of polymer solids, indicating a 96.8% conversion of monomers to polymers. The composition of the material formed begins at 80% LMA, 20% MMA and ends with about 91% LMA, 9% MMA.

Example 9 Preparation of Pour Point Depressant 9

A nitrogen-washed 3 L stainless steel reactor was charged with 268.1 parts of 100N polymer oil (bromine number less than 12). The oil is heated to 120 ° C., the desired polymerization temperature. Prepare two separate monomer mixtures: Mixture 1 contains 1033.8 parts LMA, 6.05 parts DDM and 4.03 parts tert-butyl peroctoate solution (50% in odorless inorganic spirits), mixture 2 1044.6 parts , 6.05 parts of DDM and 4.03 parts of tert-butyl peroctoate solution (50% in odorless inorganic spirits). The monomer mixtures 1 and 2 were each pumped separately into the reactor at a feed rate of 30/70 at the initial weight ratio of mixture 1 / mixture 2 to the reactor, and then the individual feed rates were adjusted to complete the monomer feed (total 90 minutes). This corresponds to a continuous change in the ratio of Mixture 1 / Mix 2 with a final ratio of 70/30. For 90 minutes of feed of monomer mixtures 1 and 2, the total feed rate increases slowly for the first 20 minutes, maintains a constant total feed rate for the next 40 minutes, and then slowly decreases to zero over the next 30 minutes. After the reactor contents are cooled to 110 ° C. and held at that temperature for an additional 30 minutes, a solution of 6.05 parts of tert-butyl peroctoate solution (50% in odorless inorganic spirit) is added over 30 minutes. The reaction solution is stirred for an additional 30 minutes, then cooled and transferred from the reactor. Near infrared analysis showed a 97.1% conversion of monomer to polymer at the end of the high temperature hold time. The product solution contains 79.1% of polymer solids (by dialysis), which corresponds to a monomer conversion of 94.1%. The polymer has a Mw of 74,800, Mn of 19.500 and a polydispersity of 3.84.

Example 10 Preparation of Pour Point Depressant 10

In a manner similar to the method described in Example 3, the monomer mixture 2 (0% SMA / 100% LMA) was continuously fed to the monomer mixture 1 fed to the reactor over the course of the polymerization, Pour point depressant polymer is prepared using 100% SMA / 0% LMA monomer mixture 1). The composition of the material formed begins with 100% SMA and ends with about 100% LMA.

Example 11 Preparation of Pour Point Depressant 11

In a manner analogous to that described in Example 3, the monomer mixture 2 (100% SMA / 0% LMA) was continuously fed to the monomer mixture 1 fed to the reactor throughout the polymerization process, while in the initial monomer mixture fed to the polymerization reactor. Pour point depressant polymer is prepared using 100% LMA / 0% SMA (monomer mixture 1). The composition of the material formed begins with 100% LMA and ends with about 100% SMA.

Example 12 (comparative example) : conventional polymerization method

A monomer mixture containing 1143.46 parts of CEMA (52%), 1033.85 parts of LMA (48%), 2.94 parts of tert-butyl peroctoate solution (50% in odorless inorganic spirit) and 12.60 parts of DDM is prepared. 60% of this mixture, 1315.71 parts, is charged to a nitrogen-washed reactor. The reactor is heated to the desired polymerization temperature of 110 ° C. and the remaining monomer mixture is fed to the reactor at a constant rate over 60 minutes. Upon completion of the monomer feed, the reactor contents were held at 110 ° C. for an additional 30 minutes and then 5.88 parts of tert-butyl peroctoate solution (50% in odorless inorganic spirits) dissolved in 312.2 parts of 100N polymer oil over 60 minutes. The reactor is fed at a uniform rate. The reactor contents are held at 110 ° C. for 30 minutes and then diluted with 980 parts of 100N polymer oil. The reaction solution is stirred for an additional 30 minutes and then transferred from the reactor. The resulting solution contains 60.2% of polymer solids, indicating 97.8% conversion of monomer to polymer.

Example 13 (Comparative Example) Physical Mixture of Two Conventional Polymers

In a manner similar to that described in Example 12, two pour point depressant polymers were prepared having the following composition: 30 LMA / 70 SMA and 70 LMA / 30 CEMA, respectively. Nearly equal portions of each polymer are combined to produce a 50/50 mixture, and the physical mixture is evaluated for low temperature performance. The overall “average” composition of the mixture is 50/50 // LMA / (35 SMA + 15 CEMA).

Examples 14-16 (Comparative Examples) : Conventional Polymers

In a manner similar to the method described in Example 12, individual pour point depressant polymers are prepared and evaluated individually or in various proportions for low temperature performance.

# 14: 70 LMA / 30 CEMA Single-Copolymer

# 15 = 48/52 mixture of 70 LMA / 30 CEMA single-copolymer and 55 LMA / 45 CEMA single-copolymer. The overall “average” composition of the mixture is 62 LMA / 38 CEMA.

# 16 = 50/50 mixture of 85 LMA / 15 CEMA single-copolymer and 55 LMA / 45 CEMA single-copolymer. The total “average” composition of the mixture is 70 LMA / 30 CEMA.

Example 17 Continuous Variable-Composition / Conventional Polymer Blend

The polymer solution of Example 3 is combined with a 94 LMA / 6 SMA single-composition copolymer (prepared in a manner similar to that described in Example 12) in a weight ratio of 65/35. The total “average” composition of the mixture is 65 LMA / 35 SMA.

As noted above, it has the properties of lubricating oil additives, such as pour point depressants, by producing a continuous variable-forming poly (meth) acrylate copolymer by causing a gradual change in monomer composition during polymerization.

Claims (14)

(A) forming a first reaction mixture comprising a monomer-containing phase in which at least two copolymerizable monomers are present in a weight ratio of X ₁ / Y ₁ to Y ₁ / X ₁ , (B) forming at least one addition reaction mixture comprising a monomer-containing phase wherein at least two copolymerizable monomers are present in a weight ratio of X _n / Y _n to Y _n / X _n , (C) initiating free-radical addition polymerization by gradually adding a first reaction mixture or a mixture of said first reaction mixture with at least one addition reaction mixture to the reactor under polymerization conditions, (c) (D) adding one or more additional reaction mixtures gradually to the reactor (i) or to the first reaction mixture (ii) added to the reactor at a point before the first reaction mixture is added to the reactor (d) and (E) maintaining the polymerization conditions until at least 90% of the at least two copolymerizable monomers are converted to the copolymer, wherein X ₁ and Y ₁ are selected from the two or more copolymerizable monomers in the first reaction mixture. Is the weight percent of two X and Y monomers, X _n and Y _n are the weight percent of two X and Y monomers of the two or more copolymerizable monomers in one or more addition reaction mixtures, and X ₁ , X _n , Y ₁ and Y _n is a value from 0 to 100%, n is a continuous integer from 2 to 10 corresponding to each of one or more addition reaction mixtures containing similar X _n and Y _n wt%, the maximum value of n being used in the process The total number of reaction mixtures, and in step (d) the gradual addition of one or more addition reaction mixtures is carried out such that at least one of the absolute values of [X _i -X _T ] or [Y _i -Y _T ] in the reactor is at least 5% X _i , X _T , Y _i and Y _T are initially (X _i and Yi) and some time later (X _T and Y _T ) is the instantaneous weight percent of two X and Y monomers added to the reactor. The method of claim 1, wherein step (d) is performed such that the absolute value of [X _i -X _T ] or [Y _i -Y _T ] is 20-50%. The process of claim 1, wherein step (d) is performed such that at least four different single-composition copolymers are produced during the polymerization and the single-composition copolymer does not represent at least 50% by weight of the variable-composition copolymer. The method of claim 1, wherein step (d) is performed such that the single-composition copolymer does not represent at least 20% by weight of the variable-composition copolymer. Continuous-variable composition copolymers prepared according to the method of claim 1. The method of claim 5, wherein the copolymerizable monomer is at least one of a vinylaromatic monomer, a nitrogen-containing ring compound monomer, an α-olefin, a vinyl alcohol ester, a vinyl halide, a vinyl nitrile, a (meth) acrylic acid derivative, a maleic acid derivative, and a fumaric acid derivative. Continuous variable-composition copolymer. The method according to claim 6, wherein the (meth) acrylic acid derivative is methyl methacrylate, butyl methacrylate, isodecyl methacrylate, lauryl-myristyl methacrylate, dodecyl-pentadecyl methacrylate, cetyl-eicosyl A continuous variable-composition copolymer selected from one or more of methacrylate and cetyl-stearyl methacrylate. The continuous variable-composition copolymer of claim 5, wherein the single composition copolymer comprises at least four different single-composition copolymers that do not represent at least 50% by weight of the variable-composition copolymer. Concentrate for use in lubricating oil comprising lubricating oil and 30 to 70% by weight of the continuous variable-composition copolymer according to claim 7. A lubricating oil composition comprising lubricating oil and from 0.05 to 20% by weight of the continuous variable-composition copolymer according to claim 7. A process for maintaining low temperature fluidity of a lubricating oil composition comprising adding 0.05 to 3 weight percent of the continuous variable-composition copolymer according to claim 7 to the lubricating oil. A continuous variable-composition copolymer, wherein the single composition copolymer comprises at least four different single-composition copolymers that do not represent at least 50% by weight of the continuous variable-composition copolymer. 13.Methyl methacrylate, butyl methacrylate, isodecyl methacrylate, lauryl-myristyl methacrylate, dodecyl-pentadecyl methacrylate, cetyl-eicosyl methacrylate and cetyl- A continuous variable-composition copolymer comprising a single-composition copolymer having monomeric units selected from two or more in stearyl methacrylates. 14 to 90% by weight of a monomeric unit selected from at least one of isodecyl methacrylate, lauryl-myristyl methacrylate and dodecyl-pentadecyl methacrylate and cetyl-acyl methacrylate 10 to 60% by weight of monomeric units Y selected from one or more of rate and cetyl-stearyl methacrylate, wherein the monomeric unit composition range of the single-copolymer is 10 to 80 for monomeric units X or Y %, Continuous variable-composition copolymer.